Key's much-vaunted "review" was very obviously a strapped chicken, with the paper seeking Cabinet permission for it also mentioning in passing possible solutions which look eerily like those finally adopted. In other words, the whole process was a sham designed to lend legitimacy to a plan the spies had already decided to enact.

The police had rather a lot to say about the final proposals; unfortunately it has all been redacted. But agencies don't normally say somethign in a Cabinet paper unless they disagree with it, so there may be a power struggle between the police and SIS over who is best suited to deal with terrorism.

Then there's this bit:
Yes, our spies want to be able to use classified information in both civil and criminal cases, and keep it secret from the other party or defendant. In other words, Ahmed Zaoui "justice" in our courts. In that case, it saw an innocent man imprisoned for years on secret evidence he was never allowed to see and could not effectively respond to. And the SIS want to introduce this as a generic rule in our courts. If you're not sure why this is a nightmare, take a look at this list of possibilities from when Britain passed a similar law in 2013 (which of course they used to shut down torture cases against them).

Open justice is a cornerstone of our human rights and democratic values. If our spies oppose it, then they're the threat, not the terrorists.

Finally, the core problem (as pointed out by Graeme Edgeler: "The problem our Government has with foreign terrorist fighters is that they follow the law, and don't commit crimes":

Combined, this doesn't paint a very pleasant picture of the policy process, or of the future direction our spies want to take us in. But if we want to stop it, we need to change the government.